Live debug on a user laptop (direct SSH, verbose MSI log) found the true SXSMSI/1603
root cause: a pre-existing 32-bit MSI Office (Office Standard 2010) blocks the 64-bit
C2R VL install. C2R log: SXSMSIValidator "32bit MSI Installation found and trying to
install 64bit C2R". MSI Office cannot coexist with C2R and never appears in C2R
ProductReleaseIds (the only place the script looked) - so it was invisible. This is
why the VM 300 pilot (no old MSI Office) succeeded and DISM/SFC didn't help.
- Get-MsiOffice: detect main MSI Office suites via ARP keys OfficeNN.<RELEASE>
(Office14.STANDARDR etc.) across both registry hives, with the Office Setup
Controller path per version.
- Remove-MsiOffice: silent uninstall via the setup controller + Display=none config
(Office 2010/2013/2016).
- Install-LatestOfficeVL now removes BOTH blockers before the VL install: retail/M365
C2R AND any MSI Office; shows them in the consent prompt; reboot+re-run after.
- Get-OfficeState telemetry now includes msiOffice=[...].
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